
#include <iostream>
#include <cstring>
using namespace std;

class Compare {
	public:
		int operator()( int x, int y ){
			return x > y ? x : y;
		}
		int operator()( int x, int y, int ){
			return x + y;
		}
		void operator()( ) {
			cout << " Nothing " << endl;
		}
	private:
};
// designer
// ------------------------------------------------------------------
// user

int main( void ) { 
	Compare c;
	int a = 10, b = 20;

	cout << c( a, b ) << endl;
	
	cout << c( a, b, 1 ) << endl;
	
	c( );

	return 0;
}

